JP2785295B2 - Leading current interruption test equipment for switchgear - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for equivalently performing a lead current interruption test of an actual system for a switch such as a circuit breaker.

B. Summary of the Invention The present invention has a current source circuit and a voltage source circuit, and automatically applies a voltage from the voltage source circuit to the test switch after opening the switch under test, and In a device that conducts an advanced current cutoff test equivalently, a series circuit of a plurality of capacitors is inserted into the voltage source circuit, and one of those connection points is grounded to measure the ground voltage of both terminals of the switch. This is equivalent to the load test.

C. Prior Art It is ideal to configure a simulation circuit similar to that of the actual system and use a three-phase real load test device as shown in Fig. 3 for the advance current interruption test of a switch such as a circuit breaker. . According to this apparatus, as shown in FIG. 4, a voltage similar to that at the time of leading current interruption in the actual system is applied to the test circuit breaker 40. However, in this case, a large-capacity generator 10, a transformer 20 and a condenser 30
Therefore, a single-phase equivalent circuit shown in FIG. 5 has been used since it requires a large amount of equipment cost.

In the circuit shown in FIG. 5, a current source circuit is constituted by an AC power source, for example, a current source transformer 2 having a primary side connected to an AC generator 1 and a voltage source having a primary side connected to the generator 1. The transformer 3 and the capacitor 4 constitute a voltage source circuit. In the figure, reference numeral 7 denotes a current limiting reactor.

To perform the test by the apparatus, first by introducing the test circuit breaker 5 and the auxiliary circuit breaker 6, the current source current I _L and a voltage source transformer 3 from the current source transformer 2 to test the circuit breaker 5 previously flowed combined current of more of the voltage source current I _H (FIG. 6 (1) -
(3)). When circuit breakers 5 and 6 are opened almost simultaneously, time t
_{At 0} , the combined current is cut off at the zero point, and the voltage V shown in FIG. 6 (5) is applied to the test circuit breaker 5 from the voltage source circuit. V _S is the secondary voltage of the voltage source transformer 3 (peak value 1.25
E).

D. Problems to be Solved by the Invention In this case, the voltage V between the poles of the test circuit breaker 5 is equal to the voltage V between the poles of the first breaking phase of the three-phase actual load test (FIG. 4 (3)). Adjust the voltage source voltage to 2.5E. Here, in the circuit of FIG. 3 of the three-phase actual load test, the voltage with respect to the ground is 1E on the load side V _L1 (FIG. 4 (1)) and 1 V on the power supply side V _S1 (4
(2)) is 1.5E, whereas in the conventional equivalent test, the condition is relaxed because one terminal is at zero potential of the ground potential.
A voltage of up to 2.5E is applied to the other terminal,
It becomes severe for the actual load test.

An object of the present invention is to make the ground voltage of both terminals of the switch equal to the actual load test.

E. Means for Solving the Problems The present invention provides a series circuit using a plurality of capacitors of a voltage source circuit, and connects the series circuit to the secondary side of the voltage source transformer and the switch under test by a current source. It is characterized in that it is connected between a connection point to which a circuit is connected and one of the connection points between the capacitors is grounded.

F. Action After the current is cut off, the residual DC voltage of the capacitor is divided, and by adjusting this voltage division ratio, the ground potential of both terminals of the test circuit breaker will be suitable for the actual system.

G. Example FIG. 1 is a diagram showing an embodiment of the present invention, this embodiment differs from the FIG. 5, three capacitors 4 ₁ - as a capacitor voltage source circuit
4 ₃ using these that it has a series circuit that are connected a series circuit of a capacitor and the secondary side of the voltage source transformer, between the connection point of the current source circuit is connected to the test switch, One of the connection points (intermediate points) between the capacitors is grounded.

When the state of the test using this apparatus will be described with reference to Figure 2, first, by introducing the test circuit breaker 5 and the auxiliary circuit breaker 6, previously synthesized current I in the test circuit breaker 5 (I _L + I _H ), And the test circuit breaker 5 and the auxiliary circuit breaker 6 are simultaneously opened.
At time t _{0, the} combined current I is cut off at the zero point, and the test circuit breaker 5
Is separated from the current source circuit. And capacitors 4 ₂ and 4 ₃
Since the connection point is grounded, the DC voltage 1.25E charged in the both ends of the capacitor ₄₁ to ₃ is divided by the dividing ratio corresponding to the capacitance of the grounding points as dividing point, this amount The compressed voltage is applied to both terminals of the test circuit breaker 5 as a ground voltage. As a result the potential of drawing lower terminal of the test circuit breaker 5 is, for example, 1E respect to the ground potential, the potential of the upper terminal is superimposed fraction of V _S and the charging voltage of the capacitor 4 ₂ with respect to the ground potential . Accordingly, the voltage shown in FIG. 2 (7) is applied between both terminals of the test circuit breaker 5, and one terminal potential is V _L1 in the three-phase real load test shown in FIG. terminal potential becomes V _S1 and each similar pattern.

H. Effect of the Invention According to the present invention, since a series circuit is formed by using a plurality of capacitors of the voltage source circuit, and an intermediate point thereof is grounded, the test cutoff is performed by selecting a voltage dividing ratio of the capacitors. The potentials at both terminals of the switch can be made equal to those in the case of a three-phase real system, and the potentials can be varied by adjusting the voltage division ratio. The test can be performed with the same severeness as the actual load test.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG.
Voltage waveform diagram, FIG. 3 is a circuit diagram showing a three-phase actual load test apparatus, FIG. 4 is a current and voltage waveform diagram, FIG. 5 is a circuit diagram showing a conventional example, and FIG. It is a waveform diagram. 1 ...... alternator, 2 ...... current source transformer, 3 ...... voltage source transformer, ₄₁ to ₃ ...... capacitor, 5 ...... test breaker, 6
…… Auxiliary circuit breaker.

Claims (1)

(57) [Claims] 1. A current source circuit including an AC power source, and a voltage source circuit having a primary side connected to the AC power source and a capacitor connected to a secondary side of the voltage source transformer. A test switch connected in parallel to the voltage source circuit and the current source circuit, and an auxiliary switch for disconnecting the test switch from the current source circuit. In a device for equivalently performing a leading current interruption test, a series circuit is formed using a plurality of the capacitors, and the series circuit is connected to a secondary side of the voltage source transformer and the switch under test by a current source circuit. A lead current interrupting test device for a switch, which is connected between a connection point to which a capacitor is connected and one of connection points between the capacitors is grounded.